Recently Pliocene and Miocene gas discoveries in offshore Mediterranean were achieved. Octopus complex structure is one of the shallow structures that exhibits a well pronounced rollover phenomena where multi bright spots (targets) are present on its crystal part. The well OCTOPUS # 1 DIR is proposed in portfouad development lease to check the potentiality of the Pliocene and Miocene sequence.
The paper discusses the blow out occurrence in said well, after the 2nd stage has been cemented and during final cut 9"5/8 casing. The 9"5/8 casing was set to cover all the high pressure interval where the maximum pore pressure is expected to be (1.75 kg/cm2/10m). And also discusses why the well stopped blowing out after 3 HRS by it self, the damage which has been happened due to cement blowing out, the operation done to replace the damaged well head and BOP stack to rescue the well. And will be discusses also the operations done to resume the drilling operations, some of these operations include, recording TDT - TEMP. Log to establish possible gas pockets trapped behind the casing, recording USIT to identify bridging, gas bucket, and fluid type behind casing. The paper discusses also annular gas migration, and the operation done to investigate and find out the reasons, which contribute to create this type of problem, and the preventive methods recommended avoiding this type of problem. Some of these methods include, adjusting cement column height, adjusting slurry thickening time, applied surface pressure on the annulus during W.O.C. increase annular mud density prior cement job, add gas block to the cement slurry, increase cement slurry mix fluid density, predicts annular gas migration by graph.